Picking out a Grade 0 Vanguard:
For this one, pick Battleraizer. Of course with his effect of summoning him in the Rear Guard circle, you can return it to your Deck, to have 1 more Stand Trigger in your Deck for later use.
For this strategy, you are utilizing Standing effects, in order to deal more attacks to your opponent. The main Grade 3 that you should be shooting for is Asura Kaizer. For Asura Kaizer's effect, you need to Drive Check a Grade 3. However, if you focus in around his effect, and max out every single Grade 3 card for Nova Grapplers, you'll have a hard time to Guard, because you'll have no Grade 0, Grade 1, or Grade 2s in your Hand. So, I only focused in on Asura Kaiser and Lion Heat, since both of them have some sort of effect to cause something to Stand.
You have 16 Grade 0 Shields (10000, unless it's a Draw Trigger, then it's 5000) and 10 Grade 1 Shields. (5000) Also, you can use NGM Prototype as an Interceptor (10000, only when he intercepts on the Field), otherwise, you have Grade 2 Shields from your Hand to block (5000). Also, you can use Twin Blader as a Guardian, by discarding a card, you can block the attack completely.
Sample Deck List:
4x Lucky Girl
4x Three Minutes
4x Round Girl Clara
3x Clay Soldier
3x Claydoll Mechanic
4x Screamin' and Dancin' Announcer Shout
4x Twin Blader
4x NGM Prototype
4x Genocide Jack
4x Hungry Dumpty
4x Asura Kaizer
4x Lion Heat
If anyone has any questions, leave a comment.